It is known that resonant circuits allow for high frequency, high amplitude AC voltages, or RF voltages to be generated without excessive power consumption.
Variable inductors using magnetic saturation are used to achieve high voltage resonance at a particular frequency as disclosed in U.S. Pat. Nos. 5,684,678 and 5,737,203 to Barrett. Electronics control of frequency and phase between a low voltage input signal and a related output signal is known from U.S. Pat. No. 3,046,490 to Marshall et al. Variable inductors, where a saturation field is applied via a single DC control winding, have been applied to power supply circuits as also is known from the Barrett disclosures.
As a general proposition an untuned load causes excessive power dissipation. Manually tuned circuitry may drift, requiring either excessive power or manual intervention. Changing the phase or amplitude on physically adjacent load elements results in the effective load capacitive changing. This in turn causes the resonant frequency to change.
Oscillators which use the resonance between a fixed inductance and the load to determine their frequency will not have controllable phase.